package com.zbangmall.util.image;


import com.zbangmall.util.image.GIF.GifEncoder;

import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Random;

/**
 * 具体用于实现生成验证码图片的方法
 */
public final class CaptchaUtil {
	protected static Font font = new Font("Verdana", Font.ITALIC | Font.BOLD, 28);   // 字体

	/**
	 * 产生0--num的随机数,不包括num
	 *
	 * @param num 数字
	 * @return int 随机数字
	 */
	public static int num(int num) {
		return (new Random()).nextInt(num);
	}

	/**
	 * 给定范围获得随机颜色
	 *
	 * @return Color 随机颜色
	 */
	protected static Color color(int fc, int bc) {
		if (fc > 255) {
			fc = 255;
		}
		if (bc > 255) {
			bc = 255;
		}
		int r = fc + num(bc - fc);
		int g = fc + num(bc - fc);
		int b = fc + num(bc - fc);
		return new Color(r, g, b);
	}


	public static boolean pngCaptcha(String randomStr, int width, int height, String file) {
		char[] strs = randomStr.toCharArray();
		try (OutputStream out = new FileOutputStream(file)) {
			BufferedImage  bi  = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
			Graphics2D     g   = (Graphics2D) bi.getGraphics();
			AlphaComposite ac3;
			Color          color;
			int            len = strs.length;
			g.setColor(Color.WHITE);
			g.fillRect(0, 0, width, height);
			for (int i = 0; i < 15; i++) {
				color = color(150, 250);
				g.setColor(color);
				g.drawOval(num(width), num(height), 5 + num(10), 5 + num(10));
			}
			g.setFont(font);
			int h = height - ((height - font.getSize()) >> 1),
					w = width / len,
					size = w - font.getSize() + 1;
			for (int i = 0; i < len; i++) {
				// 指定透明度
				ac3 = AlphaComposite.getInstance(AlphaComposite.SRC_OVER, 0.7f);
				g.setComposite(ac3);
				// 对每个字符都用随机颜色
				color = new Color(20 + num(110), 30 + num(110), 30 + num(110));
				g.setColor(color);
				g.drawString(strs[i] + "", (width - (len - i) * w) + size, h - 4);
			}
			ImageIO.write(bi, "png", out);
			out.flush();
			return true;
		} catch (IOException e) {
			return false;
		}
	}

	public static boolean gifCaptcha(String randomStr, int width, int height, String file) {
		char[] rands = randomStr.toCharArray();
		int    len   = rands.length;
		try (OutputStream out = new FileOutputStream(file)) {
			// gif编码类，这个利用了洋人写的编码类，所有类都在附件中
			GifEncoder gifEncoder = new GifEncoder();
			//生成字符
			gifEncoder.start(out);
			gifEncoder.setQuality(180);
			gifEncoder.setDelay(100);
			gifEncoder.setRepeat(0);
			BufferedImage frame;
			Color         fontcolor[] = new Color[len];
			for (int i = 0; i < len; i++) {
				fontcolor[i] = new Color(20 + num(110), 20 + num(110), 20 + num(110));
			}
			for (int i = 0; i < len; i++) {
				frame = graphicsImage(fontcolor, rands, i, width, height, len);
				gifEncoder.addFrame(frame);
				frame.flush();
			}
			gifEncoder.finish();
			return true;
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}
		return false;
	}

	/**
	 * 画随机码图
	 *
	 * @param fontcolor 随机字体颜色
	 * @param strs      字符数组
	 * @param flag      透明度使用
	 * @return BufferedImage
	 */
	private static BufferedImage graphicsImage(Color[] fontcolor, char[] strs, int flag, int width, int height, int len) {
		BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
		//或得图形上下文
		Graphics2D g2d = (Graphics2D) image.getGraphics();
		//利用指定颜色填充背景
		g2d.setColor(Color.WHITE);
		g2d.fillRect(0, 0, width, height);
		AlphaComposite ac3;
		int            h = height - ((height - font.getSize()) >> 1);
		int            w = width / len;
		g2d.setFont(font);
		for (int i = 0; i < len; i++) {
			ac3 = AlphaComposite.getInstance(AlphaComposite.SRC_OVER, getAlpha(flag, i, len));
			g2d.setComposite(ac3);
			g2d.setColor(fontcolor[i]);
			g2d.drawOval(num(width), num(height), 5 + num(10), 5 + num(10));
			g2d.drawString(strs[i] + "", (width - (len - i) * w) + (w - font.getSize()) + 1, h - 4);
		}
		g2d.dispose();
		return image;
	}

	/**
	 * 获取透明度,从0到1,自动计算步长
	 *
	 * @return float 透明度
	 */
	private static float getAlpha(int i, int j, int len) {
		int   num = i + j;
		float r   = (float) 1 / len, s = (len + 1) * r;
		return num > len ? (num * r - s) : num * r;
	}
}
